Effect of Nd2O3 and Sm2O3 on the Microstructure and Electrical Properties of WO3 Capacitor-Varistor Ceramics
The effect of Nd2O3 and Sm2O3 on the microstructure, nonlinear electrical properties, and dielectric properties of WO3-based ceramics was investigated. The dopant Nd2O3 and Sm2O3 can promote the grain growth of WO3 grains. It was also found that Nd2O3 and Sm2O3 can reduce the breakdown voltages values of WO3-based ceramics effectively, but do not strongly influence the nonlinear values. The nonlinear coefficient of doped samples was 2-3 and the barrier voltage was very low with the value of 0.04-0.08 V. Through impedance analysis, it can be found that those rare earth ions have a great influence on the dielectric properties. The dielectric constant of doped samples was higher than that of undoped samples, and the high dielectric constant makes them suitable as capacitor-varistor materials. The theory of defects in the crystal lattice was introduced to explain the nonlinear electrical behavior of the WO3-based varistor ceramics.
Takashi Goto, Yibing Cheng, Zhengyi Fu and Lianmeng Zhang
T. G. Wang et al., "Effect of Nd2O3 and Sm2O3 on the Microstructure and Electrical Properties of WO3 Capacitor-Varistor Ceramics", Advanced Materials Research, Vol. 66, pp. 9-12, 2009